The study is based on the cost of milk and marketing margins in dairy farms in Jordan and estimated cost function. This study is based on a cross section data from 33 dairy farms. In the study it was determined that the cost of raw milk production in dairy farms is 0.43 JD/ Kg. and the most important cost factors are feed cost, depreciation contributing 64%, 19%, respectively of total production cost. It was found that marketing margins of milk were 77%, econometric estimation of raw milk function using different forms showed that the linear model is superior to the other forms. The elasticity of the estimated cost function is found to be 0.20.